Insert a value into a sorted circular linked list

A circular linked list holds integers. Going round the circle once from its smallest value, the values never decrease; then the circle wraps from the largest value back to the smallest.

You get the circle opened up at some node, which need not hold the smallest value: a linked list whose first node is that node and whose last node is the one that, in the circle, links back to the first. Insert a new node holding value at a place that keeps the circle sorted. Return the circle opened at the same starting node, so the original first node stays first.

If the circle is empty, return a list with just the new node. If several places keep the circle sorted (for example when values repeat), any of them is accepted.